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Date:   Tue, 5 Jul 2022 17:45:07 +0200
From:   Gerd Hoffmann <kraxel@redhat.com>
To:     Dmitry Osipenko <dmitry.osipenko@collabora.com>
Cc:     kernel@collabora.com, David Airlie <airlied@linux.ie>,
        Thomas =?utf-8?Q?Hellstr=C3=B6m?= <thomas_os@shipmail.org>,
        Emil Velikov <emil.l.velikov@gmail.com>,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        Gurchetan Singh <gurchetansingh@chromium.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Dmitry Osipenko <digetx@gmail.com>,
        virtualization@lists.linux-foundation.org,
        Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v7 7/9] drm/virtio: Improve DMA API usage for shmem BOs
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  Hi,

> > Also note that pci is not the only virtio transport we have.
> 
> The VirtIO indeed has other transports, but only PCI is really supported
> in case of the VirtIO-GPU in kernel and in Qemu/crosvm, AFAICT. Hence
> only the PCI transport was tested.

qemu -M microvm \
  -global virtio-mmio.force-legacy=false \
  -device virtio-gpu-device

Gives you a functional virtio-gpu device on virtio-mmio.

aarch64 virt machines support both pci and mmio too.
s390x has virtio-gpu-ccw ...

take care,
  Gerd